Friday, March 8, 2013

1303.1562 (S. Afkhami et al.)

Numerical simulation of ejected molten metal-nanoparticles liquefied by
laser irradiation: Interplay of geometry and dewetting
   [PDF]

S. Afkhami, L. Kondic
Metallic nanoparticles, liquefied by fast laser irradiation, go through a rapid change of shape attempting to minimize their surface energy. The resulting nanodrops may be ejected from the substrate when the mechanisms leading to dewetting are sufficiently strong, as in the experiments involving gold nanoparticles [Habenicht et al., Science 309, 2043 (2005)]. We use a direct continuum-level approach to accurately model the process of liquid nanodrop formation and the subsequent ejection from the substrate. Our computations show a significant role of inertial effects and an elaborate interplay of initial geometry and wetting properties: e.g., we can control the direction of ejection by prescribing appropriate initial shape and/or wetting properties. We validate our computations by comparing directly with the experiments specified above involving the length scales measured in hundreds of nanometers, and with molecular dynamics simulations on much shorter scales measured in tens of atomic diameters, as in M. Fuentes-Cabrera et al., Phys. Rev. E 83, 041603 (2011). The quantitative agreement, in addition to illustrating the possibility of controlling particle ejection, suggests utility of continuum-based simulations in describing dynamics on nanoscale quantitatively, even in a complex setting as considered here.
View original: http://arxiv.org/abs/1303.1562

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